On the Characteristics of Sand Waves Formed Upon the Beds of the Open Channels and Rivers

In our preceding paper, we have studied the scale of sand waves in connexion with their influences on the characters of flow and of sand transport.In the present report, we are concerned with the same problems again, but on the more extensive experimental basis.At first, introducing a practical parameter which represents the effect of sand waves on the rate of sand transport, the formula of sediment load is derived.Next, the scale, the advance velocity, etc. of the sand waves are discussed with reference to the hydraulic conditions of the flow and the bed materials, and it is pointed out that the characters of sand waves are fairly different according as the grain diameter of sands composing the bed, corresponding to the modes of movement.Further, it is made clear that there exists a close correlation between the equivalent roughness of the flow and the scale of sand waves, and making use of these results, some considerations are shown on the law of resistance in the rivers with sand transport.* The physical meanings of this load are discussed_ in the Appendix.